* ARP no longer tries to resolve the target address in case of a link-level broadcast

(indicated by MSG_BCAST).
* ARP should now be able to resolve addresses with an unconfigured interface as well.
* datalink_is_local_address() now uses interfaces without an address as a fallback
  in case no more specific interface could be found.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@19460 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/kernel/network/datalink_protocols/arp/arp.cpp

@@ -263,11 +263,13 @@ static status_t
 arp_update_local(net_datalink_protocol *protocol)
 {
 	net_interface *interface = protocol->interface;
+	in_addr_t inetAddress;
 
 	if (interface->address == NULL) {
 		// interface has not yet been set
-		return B_OK;
+		inetAddress = INADDR_ANY;
-	}
+	} else
+		inetAddress = ((sockaddr_in *)interface->address)->sin_addr.s_addr;
 
 	sockaddr_dl address;
 	address.sdl_len = sizeof(sockaddr_dl);
@@ -280,8 +282,8 @@ arp_update_local(net_datalink_protocol *protocol)
 	memcpy(LLADDR(&address), interface->device->address.data, address.sdl_alen);
 
 	arp_entry *entry;
-	status_t status = arp_update_entry(((sockaddr_in *)interface->address)->sin_addr.s_addr,
+	status_t status = arp_update_entry(inetAddress, &address,
-		&address, ARP_FLAG_LOCAL | ARP_FLAG_PERMANENT, &entry);
+		ARP_FLAG_LOCAL | ARP_FLAG_PERMANENT, &entry);
 	if (status == B_OK)
 		entry->protocol = protocol;
 
@@ -560,7 +562,11 @@ arp_resolve(net_datalink_protocol *protocol, in_addr_t address, arp_entry **_ent
 	header.opcode = htons(ARP_OPCODE_REQUEST);
 
 	memcpy(header.hardware_sender, device->address.data, ETHER_ADDRESS_LENGTH);
-	header.protocol_sender = ((sockaddr_in *)protocol->interface->address)->sin_addr.s_addr;
+	if (protocol->interface->address != NULL)
+		header.protocol_sender = ((sockaddr_in *)protocol->interface->address)->sin_addr.s_addr;
+	else
+		header.protocol_sender = 0;
+			// TODO: test if this actually works - maybe we should use INADDR_BROADCAST instead
 	memset(header.hardware_target, 0, ETHER_ADDRESS_LENGTH);
 	header.protocol_target = address;
 
@@ -587,9 +593,6 @@ arp_resolve(net_datalink_protocol *protocol, in_addr_t address, arp_entry **_ent
 	sem_id waitSem = entry->resolved_sem;
 	benaphore_unlock(&sCacheLock);
 
-	// TODO: resend the request periodically via timer
-	//	(and abort it that way, too)
-
 	status = acquire_sem_etc(waitSem, 1, B_RELATIVE_TIMEOUT, 5 * 1000000);
 		// wait for the entry to become resolved
 
@@ -818,6 +821,7 @@ arp_send_data(net_datalink_protocol *protocol,
 		BenaphoreLocker locker(sCacheLock);
 
 		// Lookup source (us)
+		// TODO: this could be cached - the lookup isn't really needed at all
 
 		arp_entry *entry = arp_entry::Lookup(
 			((struct sockaddr_in *)&buffer->source)->sin_addr.s_addr);
@@ -827,31 +831,33 @@ arp_send_data(net_datalink_protocol *protocol,
 		memcpy(&buffer->source, &entry->hardware_address,
 			entry->hardware_address.sdl_len);
 
-		// Lookup destination (we may need to wait for this)
+		if ((buffer->flags & MSG_BCAST) == 0) {
-		entry = arp_entry::Lookup(
+			// Lookup destination (we may need to wait for this)
-			((struct sockaddr_in *)&buffer->destination)->sin_addr.s_addr);
+			entry = arp_entry::Lookup(
-		if (entry == NULL) {
+				((struct sockaddr_in *)&buffer->destination)->sin_addr.s_addr);
-			// The ARP entry does not yet exist, if we're allowed to wait,
+			if (entry == NULL) {
-			// we'll send an ARP request and try to change that.
+				// The ARP entry does not yet exist, if we're allowed to wait,
-			if ((buffer->flags & MSG_DONTWAIT) != 0) {
+				// we'll send an ARP request and try to change that.
-				// TODO: implement delaying packet send after ARP response!
+				if ((buffer->flags & MSG_DONTWAIT) != 0) {
-				return B_ERROR;
+					// TODO: implement delaying packet send after ARP response!
+					return B_ERROR;
+				}
+
+				status_t status = arp_resolve(protocol,
+					((struct sockaddr_in *)&buffer->destination)->sin_addr.s_addr, &entry);
+				if (status < B_OK)
+					return status;
+			} else {
+				// The entry exists, but we have to check if it has already been
+				// resolved and is valid.
+				status_t status = arp_check_resolved(&entry, buffer->flags);
+				if (status < B_OK)
+					return status;
 			}
 
-			status_t status = arp_resolve(protocol,
+			memcpy(&buffer->destination, &entry->hardware_address,
-				((struct sockaddr_in *)&buffer->destination)->sin_addr.s_addr, &entry);
+				entry->hardware_address.sdl_len);
-			if (status < B_OK)
-				return status;
-		} else {
-			// The entry exists, but we have to check if it has already been
-			// resolved and is valid.
-			status_t status = arp_check_resolved(&entry, buffer->flags);
-			if (status < B_OK)
-				return status;
 		}
-
-		memcpy(&buffer->destination, &entry->hardware_address,
-			entry->hardware_address.sdl_len);
 	}
 
 	return protocol->next->module->send_data(protocol->next, buffer);
@@ -905,9 +911,12 @@ arp_control(net_datalink_protocol *protocol,
 	if (op == SIOCSIFADDR && (protocol->interface->flags & IFF_UP) != 0) {
 		// The interface may get a new address, so we need to update our
 		// local entries.
+		bool hasOldAddress = false;
 		in_addr_t oldAddress = 0;
-		if (protocol->interface->address != NULL)
+		if (protocol->interface->address != NULL) {
 			oldAddress = ((sockaddr_in *)protocol->interface->address)->sin_addr.s_addr;
+			hasOldAddress = true;
+		}
 
 		status_t status = protocol->next->module->control(protocol->next,
 			SIOCSIFADDR, argument, length);
@@ -917,7 +926,7 @@ arp_control(net_datalink_protocol *protocol,
 		arp_update_local(protocol);
 
 		if (oldAddress == ((sockaddr_in *)protocol->interface->address)->sin_addr.s_addr
-			|| oldAddress == 0)
+			|| !hasOldAddress)
 			return B_OK;
 
 		// remove previous address from cache

src/add-ons/kernel/network/stack/datalink.cpp

@@ -378,6 +378,12 @@ datalink_send_data(struct net_route *route, net_buffer *buffer)
 }
 
 
+/*!
+	Tests if \a address is a local address in the domain.
+	\param _interface will be set to the interface belonging to that address
+		if non-NULL.
+	\param _matchedType will be set to either zero or MSG_BCAST if non-NULL.
+*/
 bool
 datalink_is_local_address(net_domain *_domain, const struct sockaddr *address, 
 	net_interface **_interface, uint32 *_matchedType)
@@ -388,17 +394,20 @@ datalink_is_local_address(net_domain *_domain, const struct sockaddr *address,
 
 	BenaphoreLocker locker(domain->lock);
 
+	net_interface *interface = NULL;
+	net_interface *fallback = NULL;
 	uint32 matchedType = 0;
 
-	net_interface *interface = NULL;
 	while (true) {
 		interface = (net_interface *)list_get_next_item(
 			&domain->interfaces, interface);
 		if (interface == NULL)
 			break;
-		if (interface->address == NULL)
+		if (interface->address == NULL) {
+			fallback = interface;
 			continue;
-		
+		}
+
 		// check for matching unicast address first
 		if (domain->address_module->equal_addresses(interface->address, address))
 			break;
@@ -411,10 +420,13 @@ datalink_is_local_address(net_domain *_domain, const struct sockaddr *address,
 			break;
 		}
 	}
-	
+
-	if (interface == NULL)
+	if (interface == NULL) {
-		return false;
+		interface = fallback;
-	
+		if (interface == NULL)
+			return false;
+	}
+
 	if (_interface != NULL)
 		*_interface = interface;
 	if (_matchedType != NULL)